Interferometer apparatus and associated method

An optical interferometer, comprising:

• a beamsplitter that splits the input optical signal into a first optical signal that flows along a first optical path and a second optical signal that flows along a second optical path;
• a first mirror that reflects the first signal in the first path towards the beamsplitter to form a first return path;
• a second mirror that reflects the second signal in the second path towards the beamsplitter to form a second return path;
• a first delay element including the first mirror that adjusts a time required for the first signal to flow from the beamsplitter along the first path, be reflected by the first mirror, and return along the first return path to the beamsplitter, the first delay element comprising:
• a gate electrode having a prescribed electrode shape positioned proximate a waveguide, wherein the waveguide is formed at least in part from an active semiconductor and the gate electrode is electrically separated from the active semiconductor;
• a voltage source connected to the gate electrode for applying voltage to the gate electrode, wherein the voltage causes the gate electrode to project into the waveguide a region of changeable propagation constant, said region of changeable propagation constant corresponding generally in shape to the prescribed electrode shape of the gate electrode, and
• a controller that controls a propagation constant level of the region of changeable propagation constant by varying the voltage applied to the gate electrode and thereby changing the time required for light in the first optical signal to flow from the beamsplitter along the first path, be reflected by the first mirror, and return along the first return path to the beamsplitter.

A method for implementing an optical interferometer, the method comprising:

• splitting an input optical signal using a beamsplitter into a first optical signal that flows along a first optical path and a second optical signal that flows along a second optical path;
• reflecting the first signal in the first path towards the beamsplitter to form a first return path;
• reflecting the second signal in the second path towards the beamsplitter to form a second return path;
• adjusting a time required for the first signal to flow from the beamsplitter along the first path, be reflected by the first mirror, and return along the first return path to the beamsplitter using a first delay element, the adjusting comprising:
• positioning a planar electrode proximate a waveguide, wherein the waveguide is formed at least in part from an active semiconductor and the planar electrode is electrically separated from the active semiconductor;
• applying a voltage to the planar electrode to change a level of propagation constant in a region of changeable propagation constant in the waveguide wherein the region of changeable propagation constant corresponds in shape to a shape of the planar electrode shape;
• and
• controlling a propagation constant level of the region of changeable propagation constant by varying the voltage and thereby changing the time required for light in the first optical signal to flow from the beamsplitter along the first path, be reflected by the first mirror, and return along the first return path to the beamsplitter.

An optical interferometer comprising:

• a beamsplitter that splits an input optical signal into a first optical signal that flows along a first optical path and a second optical signal that flows along a second optical path;
• a first mirror that reflects the first signal in the first path towards the beamsplitter to form a first return path;
• a second mirror that reflects the second signal in the second path towards the beamsplitter to form a second return path;
• a first delay element, that includes the first mirror, that adjusts a time required for light to flow from the beamsplitter along the first path, be reflected by the first mirror, and return along the first return path to the beamsplitter, the first delay element comprising:
• a region of changeable propagation constant disposed along a length of a waveguide, wherein light is guided within the waveguide by total internal reflection, and the waveguide is formed at least in part from an active semiconductor,
• a Field Effect Transistor portion (FET portion) including a gate electrode that is electrically separated from the active semiconductor, a source electrode, and a drain electrode;
• the gate electrode is mounted to, but electrically insulated from, the active semiconductor;
• the drain electrode and the source electrode are held at a substantially common voltage;
• wherein the gate electrode, the source electrode, and the drain electrode are positioned substantially above the waveguide, the source electrode is located on a substantially opposed side of the gate electrode from the drain electrode,
• a two-dimensional electron (hole) gas (2DEG) having a free carrier distribution that is formed on a first surface of the active semiconductor proximate the gate electrode when a voltage is applied between the gate electrode and the common voltage,
• a voltage source connected to the gate electrode for applying the voltage to the gate electrode, wherein the gate electrode projects the region of changeable propagation constant into the waveguide and thereby changes the time required for light in the first optical signal to flow from the beamsplitter along the first path, be reflected by the first mirror, and return along the first return path to the beamsplitter, and
• a controller for controlling a propagation constant level of the region of changeable propagation constant by varying the voltage produced by the voltage source.

An apparatus for implementing an optical interferometer, comprising:

• a beamsplitter that splits an input optical signal into a first optical signal that flows along a first optical path and a second optical signal that flows along a second optical path;
• a first mirror that reflects the first signal in the first path towards the beamsplitter to form a first return path;
• a second mirror that reflects the second signal in the second path towards the beamsplitter to form a second return path;
• a first delay element that including the first mirror adjusts a time required for light to flow from the beamsplitter along the first path, be reflected by the first mirror, and return along the first return path to the beamsplitter, the first delay element comprising:
• a planar electrode positioned proximate a waveguide, wherein the waveguide is formed at least in part from an active semiconductor and the planar electrode is electrically separated from the active semiconductor;
• means for changing a region of changeable propagation constant in the waveguide that substantially corresponds in shape to a shape of the planar electrode by applying a voltage to the planar electrode, and
• means for controlling a propagation constant level of the region of changeable propagation constant by varying the voltage and thereby changing the time required for light in the first optical signal to flow from the beamsplitter along the first path, be reflected by the first mirror, and return along the first return path to the beamsplitter.

A method for implementing an optical interferometer, comprising:

• splitting an input optical signal using a beamsplitter into a first optical signal that flows along a first optical path and a second optical signal that flows along a second optical path;
• reflecting the first signal in the first path towards the beamsplitter to form a first return path;
• reflecting the second signal in the second path towards the beamsplitter to form a second return path;
• adjusting a time required for light to flow from the beamsplitter along the first path, be reflected by the first mirror, and return along the first return path to the beamsplitter using a first delay element, the adjusting comprising:
• providing a gate electrode proximate a waveguide, wherein the waveguide is formed at least in part from an active semiconductor and the gate electrode is electrically separated from the active semiconductor;
• providing a body contact electrode proximate the waveguide,
• applying the first signal to the waveguide,
• applying a prescribed changeable voltage to the gate electrode that generates a region of changeable propagation constant in the waveguide and thereby changes the time required for light in the first optical signal to flow from the beamsplitter along the first path, be reflected by the first mirror, and return along the first return path to the beamsplitter.

An apparatus for implementing an optical interferometer, comprising:

• beamsplitter means for splitting an input optical signal into a first optical signal that flows along a first optical path and a second optical signal that flows along a second optical path;
• first means for reflecting the first signal in the first path towards the beamsplitter to form a first return path;
• second means for reflecting the second signal in the second path towards the beamsplitter to form a second return path;
• a delay means that adjusts a time required for light to flow from the beamsplitter along the first path, be reflected by the first means for reflecting, and return along the first return path to the beamsplitter, the delay means comprising:
• a planar electrode positioned proximate a waveguide, wherein the waveguide is formed at least in part from an active semiconductor and the planar electrode is electrically separated from the active semiconductor;
• means for applying a voltage to the planar electrode to change a level of propagation constant in a region of changeable propagation constant in the waveguide wherein the region of changeable propagation constant corresponds in shape to a shape of the planar electrode;
• and
• means for controlling the propagation constant level of the region of changeable propagation constant by varying the voltage and thereby changing the time required for light in the first optical signal to flow from the beamsplitter along the first path, be reflected by the first means for reflecting, and return along the first return path to the beamsplitter.

An apparatus for implementing an optical interferometer, comprising:

• a beamsplitter that splits the input optical signal into a first optical signal that flows along a first optical path and a second optical signal that flows along a second optical path;
• a first mirror that reflects the first signal in the first path towards the beamsplitter to form a first return path;
• a first programmable delay generator that includes the first mirror that adjusts a time required for light to flow from the beamsplitter along the first path, be reflected by the first mirror, and return along the first return path to the beamsplitter, the first programmable delay generator comprises:
• a first planar electrode positioned proximate a first waveguide, wherein the first waveguide is formed at least in part from an active semiconductor and the first planar electrode is electrically separated from the active semiconductor that forms part of the first waveguide
• means for changing a first region of changeable propagation constant in the first waveguide that substantially corresponds in shape to a shape of the first planar electrode by applying a first voltage to the first planar electrode, and
• means for controlling a first propagation constant level of the first region of changeable propagation constant by varying the first voltage and thereby changing the time required for light in the first optical signal to flow from the beamsplitter along the first path, be reflected by the first mirror, and return along the first return path to the beamsplitter;
• a second mirror that reflects the second signal in the second path towards the beamsplitter to form a second return path;
• and
• a second programmable delay generator that includes the second mirror that adjusts a time required for light to flow from the beamsplitter along the second path, be reflected by the second mirror, and return along the second return path to the beamsplitter, the second programmable delay generator comprises:
• a second planar electrode positioned proximate a second waveguide, wherein the second waveguide is formed at least in part from an active semiconductor and the second planar electrode is electrically separated from the active semiconductor that forms part of the second waveguide;
• means for changing a second region of changeable propagation constant in the second waveguide that substantially corresponds in shape to a shape of the second planar electrode by applying a second voltage to the second planar electrode, and
• means for controlling a first propagation constant level of the second region of changeable propagation constant by varying the second voltage and thereby changing the time required for light in the second optical signal to flow from the beamsplitter along the second path, be reflected by the second mirror, and return along the second return path to the beamsplitter.

A method for implementing an optical interferometer, comprising:

• splitting an input optical signal into a first optical signal that flows along a first optical path and a second optical signal that flows along a second optical path using a beamsplitter;
• reflecting the first signal in the first path towards the beamsplitter to form a first return path;
• adjusting a first time required for light to flow from the beamsplitter along the first path, be reflected, and return along the first return path to the beamsplitter, the adjusting the first time comprising:
• positioning a first planar electrode proximate a first waveguide, wherein the first waveguide is formed at least in part from an active semiconductor and the first planar electrode is electrically separated from the active semiconductor that forms part of the first waveguide;
• changing a first region of changeable propagation constant in the first waveguide that substantially corresponds in shape to a shape of the first planar electrode by applying a first voltage to the first planar electrode, and
• controlling a propagation constant level of the first region of changeable propagation constant by varying the first voltage and thereby changing the first time required for light in the first optical signal to flow from the beamsplitter along the first path, be reflected, and return along the first return path to the beamsplitter;
• reflecting the second signal in the second path towards the beamsplitter to form a second return path;
• and
• adjusting a second time required for light to flow from the beamsplitter along the second path, be reflected, and return along the second return path to the beamsplitter, the adjusting the second time comprising:
• positioning a second planar electrode proximate a second waveguide, wherein the second waveguide is formed at least in part from an active semiconductor and the second planar electrode is electrically separated from the active semiconductor that forms part of the second waveguide;
• changing a second region of changeable propagation constant in the second waveguide that substantially corresponds in shape to a shape of the second planar electrode by applying a second voltage to the second planar electrode, and
• controlling a propagation constant level of the second region of changeable propagation constant by varying the second voltage and thereby changing the time required for light in the second optical signal to flow from the beamsplitter along the second path, be reflected by the second mirror, and return along the second return path to the beamsplitter.